17.1.9 unbound forware reverse lookup

[chris786]

Hello,
i used unbound for a internal DNS. The internal Domain for my Network is .nodomain . All querys for this Domain will be forwarded to an other internal DNS-Server.  So far everything works.

But i need to forward Reverse Lookups for the internal Domain to an other Server. In the GUI isn't such option.

So i put under:
Services: Unbound DNS: General Custom options this:

server:
        local-zone: "168.192.in-addr.arpa."  nodefault
stub-zone:
        name: "168.192.in-addr.arpa."
        stub-addr: 192.168.2.50

Now the reserve lookups work. Later i try it again an i got:
 

dig -x 192.168.2.198             

; <<>> DiG 9.9.5-9+deb8u11-Debian <<>> -x 192.168.2.198
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 41408
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;198.2.168.192.in-addr.arpa.   IN   PTR

;; AUTHORITY SECTION:
168.192.in-addr.arpa.   3580   IN   SOA   prisoner.iana.org. hostmaster.root-servers.org. 1 604800 60 604800 604800

;; Query time: 0 msec
;; SERVER: 192.168.2.188#53(192.168.2.188)
;; WHEN: Thu Jul 13 12:32:00 CEST 2017
;; MSG SIZE  rcvd: 132

Than i restart the unbound service, and it works for a short time.

Has anyone on Idea what is wrong?